Vulnerability details
CVE-2026-33943
Red Hat OpenShift Container Platform 4capricorn86 happy-dom
Happy DOM ECMAScriptModuleCompiler: unsanitized export names are interpolated as executable code
CVSS 3.1
8.8High
Official description
Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. In versions 15.10.0 through 20.8.7, a code injection vulnerability in `ECMAScriptModuleCompiler` allows an attacker to achieve Remote Code Execution (RCE) by injecting arbitrary JavaScript expressions inside `export { }` declarations in ES module scripts processed by happy-dom. The compiler directly interpolates unsanitized content into generated code as an executable expression, and the quote filter does not strip backticks, allowing template literal-based payloads to bypass sanitization. Version 20.8.8 fixes the issue.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 8.8High | 3.1 | CVEProject cvelistV5 (CNA) (GitHub_M) | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
| 8.8High | 3.1 | CVEProject cvelistV5 (CNA) (redhat-SADP) | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| Red Hat | Red Hat OpenShift Container Platform 4 | All | CVEProject cvelistV5 (CNA) |
| capricorn86 | happy-dom | >= 15.10.0, < 20.8.8 | CVEProject cvelistV5 (CNA) |
References and advisories
6- https://github.com/capricorn86/happy-dom/commit/5437fdf8f13adb9590f9f52616d9f69c3ee8db3c x_refsource_MISC
- https://github.com/capricorn86/happy-dom/releases/tag/v20.8.8 x_refsource_MISC
- https://github.com/capricorn86/happy-dom/security/advisories/GHSA-6q6h-j7hj-3r64 x_refsource_CONFIRM
- https://access.redhat.com/security/cve/CVE-2026-33943 vdb-entryx_refsource_REDHAT
- https://bugzilla.redhat.com/show_bug.cgi?id=2452522 issue-trackingx_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33943.json x_sadp-csaf-vex
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Details
- Published
- 2026-03-28
- Last updated
- 2026-07-15
- State
- Published
- Assigner (CNA)
- GitHub_M
Exploit prediction (EPSS)
0.64%
Probability of exploitation in 30 days
51.2%
Percentile (among all CVEs)
SSVC assessment (CISA)
- Automatable
- No
- Exploitation
- Proof of concept
- Technical impact
- Total
Weaknesses (CWE)
- CWE-94Improper Control of Generation of Code ('Code Injection')
- CWE-917Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')